Unusual Temperature Dependence of Water Sorption in Semicrystalline Hydrogels

Abstract

Water vapor sorption is a ubiquitous phenomenon in nature and plays an important role in various applications, including humidity regulation, energy storage, thermal management, and water harvesting. In particular, capturing moisture at elevated temperatures is highly desirable to prevent dehydration and to enlarge the tunability of water uptake. However, owing to the thermodynamic limit of conventional materials, sorbents inevitably tend to capture less water vapor at higher temperatures, impeding their broad applications. Here, an inverse temperature dependence of water sorption in poly(ethylene glycol) (PEG) hydrogels, where their water uptake can be doubled with increasing temperature from 25 to 50 °C, is reported. With mechanistic modeling of water-polymer interactions, this unusual water sorption is attributed to the first-order phase transformation of PEG structures, and the key parameters for a more generalized strategy in materials development are identified. This work elucidates a new regime of water sorption with an unusual temperature dependence, enabling a promising engineering space for harnessing moisture and heat.

Injectable thermogel constructed from self-assembled polyurethane micelle networks for 3D cell culture and wound treatment

“…As the solid content rises, amphiphilic particles tend to aggregate and accumulate more densely, promoting the transition of latex particles from a sol state to a gel state. 35,36 While, as the concentration increases, particles become aggregation, and the size increases (Fig. S6, ESI †).…”

Polymer-Based Hydrogels Applied in Drug Delivery: An Overview

“…These hydrogels can undergo controlled swelling and exhibit tunable mechanical properties, allowing them to mimic the physical and mechanical properties of natural tissues [190,191]. Additionally, hydrogels can be engineered to respond to external stimuli such as changes in temperature [192,193], pH [193,194], or light, making them valuable for applications such as targeted drug delivery or biosensing [13,15,69,103].…”

“…Polymer-based hydrogels have a wide range of applications in various fields, including drug delivery systems [195,196], the food industry [174], wastewater treatment [74], biosensors [103], water storage granules [192,197], coating [108,140], corrosion inhibitors [11,17,23], and actuators [23], as shown in Figure 1. They provide a versatile platform for the controlled release of drugs [111,119], scaffolds for tissue regeneration [198,199], wound dressings [46], and biocompatible materials for medical devices [86].…”

“…Temperature-responsive polymer-based hydrogels are a type of hydrogel that exhibit changes in their swelling behavior or sol-gel transition in response to changes in temperature [74,75,131,192,193]. These hydrogels are designed to undergo a volume phase transition at a specific temperature, known as the lower critical solution temperature (LCST) or an upper critical solution temperature (UCST) [23,192,193]. The transition can be reversible or irreversible, depending on the specific polymer and formulation used.…”

“…This allows for the fine-tuning of the hydrogel properties to match specific application requirements. Temperature-responsive polymerbased hydrogels have a wide range of applications, particularly in drug delivery systems and tissue engineering [11,23,192,193]. They can be used as carriers for controlled drug release, where the drug is released at a higher rate above the LCST due to the collapse of the hydrogel.…”